from typing import List
"""
    344. 反转字符串
    编写一个函数，其作用是将输入的字符串反转过来。输入字符串以字符数组 s 的形式给出。
    不要给另外的数组分配额外的空间，你必须原地修改输入数组、使用 O(1) 的额外空间解决这一问题。
    
    示例 1：
        输入：s = ["h","e","l","l","o"]
        输出：["o","l","l","e","h"]
    示例 2：
        输入：s = ["H","a","n","n","a","h"]
"""

class Solution:
    def reverseString(self, s: List[str]) -> None:
        """
        Do not return anything, modify s in-place instead.
        """
        right = len(s) - 1
        left = 0
        while left < right:
            tem = s[left]
            s[left] = s[right]
            s[right] = tem
            left += 1
            right -= 1